Biology 9700 · AS & A Level · Protein synthesis

Protein synthesis — practice question

A student looked into the initial rate at which catalase breaks hydrogen peroxide down into oxygen and water: $2\text{H}_2\text{O}_2 \xrightarrow{\text{catalase}} \text{O}_2 + 2\text{H}_2\text{O}$ Oxygen volume was measured for $140\ \text{s}$. The findings are shown in Fig. 2.1.
(a(i))[2]

From Fig. 2.1, calculate the initial rate of reaction in $\text{cm}^3\ \text{s}^{-1}$. Show the steps in your calculation.

(a(ii))[3]

Describe how the volume of oxygen collected changes in Fig. 2.1.

(ii)[3]

Explain how the volume of oxygen collected changes as shown in Fig. 2.1.

(b)[4]

Use the information in Fig. 2.2 to explain how copper ions affect the action of an enzyme, such as catalase.

(c)[3]

Enzyme molecules inside cells eventually cease functioning and are degraded. Outline how cells replace the enzymes that have been broken down.

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This 15-mark question has a full step-by-step worked solution and mark scheme. One marking point: A tangent is drawn on the graph as close as possible to time $0$

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